Paying Stamp Duty on share purchases: the current 30-day rule before the 2027 reform

Companies buying shares through a stock transfer form can have a Stamp Duty payment obligation that sits outside normal Corporation Tax and PAYE processes. As of October 2026, the existing Stamp Duty rules still apply, even though the government has published draft legislation for a new Securities Transfer Tax planned for 2027.

Current Stamp Duty still applies to relevant stock transfer forms in 2026

GOV.UK says Stamp Duty is payable where shares are bought using a stock transfer form and the consideration is more than £1,000, subject to exemptions and reliefs. The current rate is 0.5 percent of the consideration, rounded up to the nearest £5.

Do not confuse this with Stamp Duty Reserve Tax on paperless share purchases or Stamp Duty Land Tax on property. A company acquisition can involve several taxes, and finance should identify which instrument actually triggers each payment.

The stock transfer form and payment are due within 30 days

HMRC says the company must send the stock transfer form to the Stamp Office and pay Stamp Duty no later than 30 days after the form is signed and dated. Where the deadline falls on a weekend or bank holiday, payment should reach HMRC by the end of the previous working day.

Put the deadline into the transaction closing checklist. A share acquisition can have dozens of completion documents, but the tax payment is not automatically handled by Companies House or the bank financing the deal.

Calculate 0.5 percent and round up to the nearest £5

For a £2 million share purchase, the ordinary 0.5 percent calculation is £10,000 before considering any relief or special rule. For smaller transactions, HMRC's rounding rule can create a slightly different effective percentage because the duty is rounded up to the next £5.

Have the tax adviser confirm consideration and reliefs before finance sends money. Deferred consideration, connected-company transactions or reorganisations can require more analysis than multiplying the headline purchase price by 0.5 percent.

Use the payment reference HMRC requires for Stamp Duty

GOV.UK's Stamp Duty payment guidance says the bank transfer needs a payment reference that lets HMRC identify the payment. Its published method uses identifying information such as payer name and payment amount according to the current instructions.

Do not reuse an HMRC PAYE or Corporation Tax beneficiary reference. Stamp Duty is administered separately. Keep the bank confirmation with the stock transfer form and email or submission evidence sent to the Stamp Office.

Do not register the shares prematurely where stamping requirements still apply

Company secretarial and legal teams should coordinate the tax process with the share-register update. The purchaser needs evidence that the transaction has met applicable Stamp Duty requirements before the transfer is treated as fully completed for corporate-record purposes.

Finance should therefore confirm the tax-payment status to the solicitor or company secretary rather than assuming that sending the purchase price to the seller completed every step of the acquisition.

A new Securities Transfer Tax is planned for 2027, but it is not the current 2026 payment regime

HMRC published draft legislation in July 2026 for a new Securities Transfer Tax intended to replace Stamp Duty and Stamp Duty Reserve Tax on securities transfers in 2027. The proposed regime is designed to be digital and self-assessed.

Until the new rules take effect, businesses should follow the current Stamp Duty and SDRT framework. For a transaction completing in late 2026 or crossing the reform date, confirm the live law at completion rather than assuming the future regime has already replaced the existing 30-day process.

For acquisitions, include Stamp Duty in the sources-and-uses schedule. The buyer may fund the share price, legal fees and debt refinancing at completion while the Stamp Duty cash leaves up to 30 days later. Reserving the tax at completion prevents the company from treating the post-deal bank balance as entirely free working capital.

Because the 2027 Securities Transfer Tax reform is still future law as of October 2026, transaction documents should state which regime is expected to apply and require advisers to confirm the position near completion. Deals signed in 2026 but completing in 2027 are exactly where assuming today's process or tomorrow's process without a fresh check can create errors.